THIS INVENTION relates to a track shoe for a crawler track. In particular, the invention is directed to a crawler track shoe for an electric mining shovel, although the invention is not limited to that particular use.
Some items of large mining machinery, such as excavators and shovels, are fitted with crawler tracks for locomotion. The individual links of the crawler tracks are known as xe2x80x9cshoesxe2x80x9d. These shoes are linked together by pins to form an endless articulated track, each track being mounted on support rollers with sprockets at either end.
The track shoes must support a heavy weight, and are subject to high pressures. Further, the tracks are often required to operate in harsh conditions, such as stony or rock-strewn ground. Hence, the track shoes must be of sufficient size and strength to withstand such conditions.
Track shoes are normally made of cast steel or other ferrous material, and then subjected to further foundry processing, such as heat treatment, to increase strength.
To cope with the high loads and harsh operating conditions, track shoes have been made bigger, with some shoes being over 2 meters wide. However, increasing the size of the shoes increases their cost and weight. The heavier shoes are harder to handle, and increase the load to be moved.
It is known to use hollow shoes having a plurality of internal walls or ribs for strengthening. However, such internally-ribbed hollow shoes are relatively expensive and difficult to manufacture, and have limited application.
It is an object of this invention to provide an improved crawler track shoe which overcomes or ameliorates the abovedescribed disadvantages, or which at least provides the consumer with a useful choice.
In one broad form, the invention provides a track shoe for a crawler track, the track shoe having a hollow body with top and bottom portions separated by a void, characterised in that the shoe includes a supporting portion located in the void and extending between the top and bottom portions.
The term xe2x80x9chollow bodyxe2x80x9d as used in this specification is intended to mean that the body has one or more voids or cavities therein.
Typically, the supporting portion is a pillar-like portion which is integrally cast with the body. The pillar-like portion is advantageously located under the main loadbearing region, and is surrounded by the void within the hollow body.
The pillar-like portion bears most of the load carried by the shoe, thereby enabling the thickness of the shoe walls to be minimised. The thickness may be optimised by computer-aided design using finite element analysis.
In order that the invention may be more fully understood and put into practice, a preferred embodiment will now be described with reference to the accompanying drawings.